This invention relates to a locking device and particularly to a deadbolt type door lock.
For security reasons, it is necessary to lock entrance doors of homes and other buildings when they are unattended. For example, schools have numerous entrance doors which must all be securely locked after hours to prevent vandalism. School doors are typically chained and locked closed. The advantage of using chains is that they make it easy to visually inspect the door to insure that it is locked. Chains are, however, cumbersome to use and their use may violate local public building laws. Presently available deadbolt type locks do not provide a conspicuous visible indication of the locked and unlocked states which is advantageous to enable the lock to be easily checked from a distance by a custodian or security officer. For many door lock applications, such as schools, it is desirable to prevent entrance doors from being locked by an unauthorized person. Accordingly, it is further desirable to provide a door lock which can be secured in either its locked or unlocked conditions so that the state of the lock can be changed only by an authorized individual.
The above desirable features are achieved in accordance with this invention. The improved deadbolt door lock according to this invention employs a bolt assembly which can be secured in its locked or unlocked states and is adapted for use with a padlock which can be installed in different orientations and having indicia on its two major face surfaces for indicating the state of the lock.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.